# Gauge coupling unification without leptoquarks

## TL;DR

This paper presents a novel approach to gauge coupling unification that eliminates the need for leptoquarks, potentially resolving hierarchy and proton stability issues within grand unified theories.

## Contribution

It introduces a method to achieve gauge unification without scalar or vector leptoquarks using nonlinear gauge-invariant constraints, applicable to SU(5) and other groups.

## Key findings

- Proposes gauge unification without leptoquarks.
- Ensures proton stability in the model.
- Addresses hierarchy problem differently.

## Abstract

We propose an interpretation of the gauge coupling unification scale which is not related to any new particle threshold. We revisit Grand Unified Theories and show that it is possible to completely eliminate the scalar as well as vector leptoquarks from the particle physics spectrum. As a consequence, in our approach the gauge hierarchy problem is put on different grounds, and the proton may be absolutely stable. In order to achieve that, we employ a number of nonlinear gauge-invariant constraints which only affect the superheavy degrees of freedom. We illustrate our considerations in a model based on the SU(5) group, with the generalization to other groups being straightforward. We discuss how scale or conformal invariance may be added to our proposal.